How to find out your entire genetic make-up

That’s me: Each human genome contains three billion proteins, or 262,000 pages of letters.

Should everyone get their genome sequenced? A new, handheld device could allow people to analyse their DNA from “the comfort of their own home”. But they might not like what they find…

When scientists decided to sequence the human genome for the first time, it took them 13 years, more than 1,000 researchers, and $2.7 billion. The project was completed in 2003, when it was described as “one of the most exciting chapters of the book of life”. For the first time ever, scientists could read the entire DNA “recipe” for a single person.

Fifteen years later, scientists are still learning how to interpret the information they read. It now takes around $1,000 and a well-stocked lab to sequence someone’s genome.

But maybe not for much longer: a company in Oxford has invented a small device, the size of a mobile phone, that could soon offer genome sequencing “as a routine tool, perhaps something people can do in their own home,” according to one scientist. The details of its first successful attempt were published on Monday.

The device works by passing DNA strands through a tiny hole called a “nanopore”. There are four proteins that build the genes in our DNA, symbolised by the letters A, C, G and T. As they pass through the machine, they each give off an electrical signal, which can be read and recorded until scientists have the person’s full genetic information.

The human genome is complex. We each have around 20,000 genes. They decide things like our eye colour, the shape of our face, our predisposition for certain tastes or talents.

They do not entirely determine who we are, because we are also shaped by our upbringing and environment. But they are a “blueprint”.

When it comes to medicine, sometimes a single gene mutation can lead to a life-changing disorder, like cystic fibrosis or Huntington’s Disease. In other cases, our genes only tell us if we have a higher risk of developing a disease — such as Alzheimer’s — later in life. They can also tell us how we react to certain drugs.

For this reason, scientists predict that genetics will become an increasingly important part of healthcare.

But should everyone — including healthy people — get their genome sequenced?

Can you handle the truth?

Absolutely, say some. If you know you have a higher risk of developing a certain disease, you can start making lifestyle changes to reduce that risk. Parents could predict whether their children will inherit genetic problems. And the more people get it done, the more scientists will learn about how to read the results. Everybody wins.

There is such a thing as too much information, argue others. Sometimes a genome reveals “faults” that have no actual effects. Someone could spend their whole life dreading a disease which never comes — or they could find out that it was inevitable, and feel hopeless in the face of that knowledge. It is better not to know.

You Decide

  1. Given the chance, would you want to know what your genes said about you — and your future health?
  2. Should everyone have their genome sequenced?

Activities

  1. Look at the diagram at the top of this article. Write a short explanation for each of the features it illustrates.
  2. Imagine that the device described in this article is now available for ordinary people to buy and use at home. Write an article arguing why everyone should — or should not — have one.

Some People Say...

“Genetics will lead to a world where there is a sympathy for the underdog.”

James Watson, co-discoverer of DNA structure

What do you think?

Q & A

What do we know?
The company, called Oxford Nanopore, has already used its handheld device to track the spread of Ebola during the outbreak that began in 2014. Several different companies have already made genome analysis available to the public. 23andMe, for example, offers a “health and ancestry” analysis for £149 in the UK.
What do we not know?
How much of ourselves and our personalities is determined by genetics. As the geneticist Craig Venter explains, it plays a significant role in the “set of operating tools that each of us have”. But it does not determine what we will do with those tools. We also do not know exactly how many of our characteristics are decided by genetics — scientists have spent years trying and failing to locate a “gay gene” that determines sexuality, for example.

Word Watch

DNA
Deoxyribonucleic acid — the thread that carries the genetic codes for an organism. It has a twisted structure known as a double-helix.
Published
The details of the first human genome sequenced using nanopore technology were published in the journal Nature Biotechnology.
A, C, G and T
These are short for the names of the proteins: adenine, cytosine, guanine, and thymine.
20,000 genes
Around 99.9% of these are identical to every other human on Earth. But the other 0.1% make us unique.
Cystic fibrosis
A rare genetic condition which mostly affects a person’s lungs. It is caused by mutations in both copies of genes for the CFTR protein. One in 25 people has this mutation, but it must be passed on by both parents.
Huntington’s Disease
A condition caused by a mutation in one of the copies of the Huntingtin gene. It causes a person’s physical and mental abilities to gradually decline, usually between the ages of 30 and 50.